Fish welfare in research and aquaculture
The animal article of the month for January is ‘Review: Assessing fish welfare in research and aquaculture, with a focus on European directives‘
In recent years, teleost fish have been increasingly exploited as animal models for scientific research in both the biomedical and ecological fields by using various ‘omics’ approaches, as they offer several practical advantages compared with mammals or other vertebrates. Moreover, the number of fish raised in aquaculture farm is constantly increasing, as aquaculture is not only a massive industrial activity that integrates human diet with high-quality food, but it also helps in restocking fish populations for both commercial and conservation purposes. Consequently, ensuring fish welfare is important in both scientific research and aquaculture contexts. Despite some common elements, these two contexts differ at the level of the dimensional scale, objectives, husbandry conditions, species and number of captive fish maintained.
Dealing with animal health, it is important not to confuse the terms “welfare”, “wellness” and “stress”. A definition of welfare is not only based on physical health but also on the lack of mental suffering. Therefore, the concept of welfare is wider than the simple concept of wellness, which refers more to physical health and the avoidance of prolonged stress. Stress can be defined as a condition in which homeostasis, that is the dynamic balance of the animal organism, is disturbed by intrinsic or extrinsic stimuli, commonly called stressors. The stress response is an adaptive function and it does not necessarily signify suffering or poor welfare.
Ensuring the welfare of fish is a complex issue due to the high number of species-specific factors and aspects that must be known, considered, set or monitored, including the physical–chemical parameters of water, welfare indicators, environmental complexity, stocking density and foraging and social behaviours of the animals.
In Europe, the use of fish for human purpose is regulated by specific Directives and Recommendations based on the assumption that vertebrate animals should always be treated as sentient creatures and that their use in scientific procedures must be restricted to research areas that may ultimately benefit human or animal health or the environment. The Directive 2010/63/EU on the protection of animals used for scientific purposes covers ‘vertebrate animals including cyclostomes, cephalopods […] as there is scientific evidence of their ability to experience pain, suffering, distress and lasting harm’.
The European Directives and Recommendations on farmed fish are important steps forward to ensure the welfare of fish used for scientific purposes and commercial activity. However, despite these efforts, information provided about fish sometimes appears too generic and concise to serve as a useful tool to guarantee fish health. The wide biological diversity of fish species and their different physiological and behavioural needs are scarcely considered.
Although European legislation is a useful and informative tool, further and more in-depth research is needed to bridge the cognitive gaps in the above mentioned areas. It is crucial to produce global legislation ensuring fish welfare in the contexts of both research and aquaculture that prevent different countries from applying different animal treatment procedures.
This article is freely available for one month: ‘Review: Assessing fish welfare in research and aquaculture, with a focus on European directives‘
Author: M. Toni et al.